Multiple speed switch mechanism



Aug. 23, 1960 c. B. MCCATHRON MULTIPLE SPEED SWITCH MECHANISM 2 Sheets-Sheet 1 Filed Jul}; 13, 1959 1960 c. B. MCCATHRON 2,950,367

MULTIPLE SPEED SWITCH MECHANISM Filed July 15, 1959 2 Sheets-Sheet 2 IN I "ENTO R.

6 /0001 3 @Qf/Z'rurz B Y A TTOR/VEV United States Patent MULTIPLE SPEED SWIT CH MECHANISM Claude B. McCathron, Milwaukee, Wis., assiguor to General Motors Corporation, Detroit, Micln, a corporation of Delaware Filed'July 13, 1959, Ser. No. 826,791

9 Claims. (Cl. 200-450) The present device relates to a speed switch mechanism using the flyball governor principle to operate a plurality of self-contained switches as a function of rotational speed. Each of the electrical switches is operated at a different predetermined speed, the setting of which is adjustable independently of the other.

The subject device is an improvement over speed switches of this general type, such as shown in Williams 2,457,192, in being constructed with both ends of the drive shaft extending exteriorly of mechanism body so as to permit tandem coupling of such devices or the driving of other accessories such as tachometers. Further, the present device permits a type of independent switch adjustment not heretofore possible with known switches of this type.

In general, the present speed switch mechanism includes a floating lever disposed intermediate a pair of longitudinally spaced switch devices and a fiyweight thrust device centrally disposed on the opposite side of the lever relative to the switch devices. A plurality of different strength spring devices are disposed proximate each of said switch devices such that as the rotative speed of a shaft member increases a central thrust force will be created causing the collapse of the weakest spring device thereby actuating the first switch. A further increase in speed will result in the collapse of the second spring device to actuate the second switch. In this way the floating lever, in eflect, pivots first about the strongest spring device, then subsequently pivots about the first spring device.

In a device such as shown in the aforenoted Williams patent, a single adjustable spring is provided whereby the actuation of each of the switches is affected by an adjustment of the spring. In the present device, on the other hand, independentspring devices are provided whereby adjustment of each switch may be achieved without affecting the operation of the other switch. In addition, the Williams type speed switch is constructed in such a way as not to permit the coupling of a plurality of such devices or the driving of other accessories therefrom. The subject device, on the other hand, through its unique design permits coupling, accessory drive and independent switch actuation adjustment thereby greatly enhancing the utility of the mechanism.

The details as well as other objects and advantages of the present device will be apparent from a perusal of the detailed description which follows.

In the drawings:

Figure 1 is a sectioned elevational view showing the subject mechanism;

Figure 2 is a partially sectioned elevational view showing the switch devices; a

Figure 3 is a plan view of Figure 1;

Figures 4-6 are detail views of the pivot plate;

, Figure 7 is a detail view of the upper actuating member; and

Figures 8-10 are schematic representations of the various operating positions of the pivot plate.

"ice

Referring to Figure 1, a housing 10 is shown and includes an upwardly opened end 12 and a relatively closed end 14 having a bearing supporting opening 16 therein. A centrally apertured cover plate 18 is adapted to enclose the upper end 12 of the housing and is secured to the latter through suitable screw members 20. A first ball bearing member 22 is mounted in housing 10 and includes an outer race 24 fixed within housing opening 16 against rotation and an inner race 26 fixed to a hub member 28 which is in turn fixed to a rotatable shaft member 30. A solid bearing, e.g., carbon, is fixed within the aperture of cover plate 18 and is adapted to support the other end of shaft 30.

A pair of flyweight members 32 are pivotally supported upon flange 34 of hub 28 through pins 36 and, accordingly, rotate with shaft 30. The weighted portions 38 of flyweights 32 are axially spaced from fiyweight supporting pins 36.

A first actuator member 40 is slidably mounted on hub 28 and includes a portion 42 adapted to be engaged by a foot portion 44 on each of the flyweights 32. A radially disposed pin 46 is fixed to shaft 30 and is adapted to coact with a slot 48 in actuator 40 to limit the latters axial movement.

A second ball bearing member is indicated generally at '50 and includes an inner race slidably mounted on hub 28 and which race is rotatable with the hub and shaft 30.

A second actuator device 52, best seen in Figures 1 and 7, includes an annular ring 54 supported upon the outer race of bearing 50. A pair of pins 58 are fixed to annular ring 54 of actuator 52 and are disposed on diametrically opposite sides of the rotatable shaft 30. The ends of pins 58 extending from ring 54 are tapered to coact with correspondingly shaped recesses 60 in a pivot plate or floating lever 62.

Pivot plate 62 is shown in detail in Figures 4-6 and includes a central aperture 64 through which one end of rotatable shaft 30 is adapted to extend. Pivot plate or floating lever 62 is elongated and tapered at either end and includes raised portions or bosses 66 and 68 which, as will subsequently be seen, provide retaining seats for coil springs 70 and 72.

As best seen in Figure 2, a bracket member 74 having a pair of spaced legs 76 and 78 is mounted on or formed integrally with cover plate 18. Bracket legs 76 and 78 have two functions the first of which is to provide, respectively through screws 80 and 82 and washers 84 and 86, seats for one end of coil springs 70 and 72. The other function of bracket legs 76 and 78 is to provide support for first and second switch devices 88 and 90.

Referring first to the spring supporting function of bracket legs 76 and 78, it is to be understood that until the rotative speed of shaft 30 has reached a first predetermined value the force of springs 70 and 72 is such as to bias the various actuator parts into the retracted or inoperative position shown in Figures 1, 2 and 8. In this position neither of the switch devices 88 or 90 will be actuated.

As already noted, bracket legs 76 and 78 support first and second springs 70 and 72 proximate pivot plate or floating lever 62. Before describing the mechanism further, it is to be noted that the self-contained switches 88 and 90 may be of any well known type and do not, per se, constitute any part of the present invention. It will suflice for present purposes to notethat each of the switch devices 88 and 90 includes a slidable actuator or plunger 92 and 94 adapted to be engaged and thereby actuated by plate 62 in turn actuating any suitable device to be controlled by the speed switch mechanism.

Returning now to the description of the actual operation of the speed switch mechanism, it is to be noted that the first spring element 70 is intended to be weaker than the second spring element 72. Accordingly, as the rotative speed of shaft 30 exceeds a first predetermined value the centrifugal forces actuating on flyweights 32 will exceed the force of the first spring element 70' and in so doing will move the first actuator 40, bearing member 50. and the second actuator 52 axially toward the open end 12 of housing 10. This movement will cause pins 58 to pivot plate 62 about the stronger spring element 72. Plate 62 accordingly engages with the plunger 92 and actuates the first switch device 88. At this point in the operation of the speed switch mechanism the pivot plate or floating lever 62 is in the position shown schematically in Figure 9. As the rotative speed of shaft 30 continues to increase beyond a second predetermined value the stronger spring element 72 likewise begins to collapse under which circumstances pivot plate or lever 62 begins to pivot around plunger 92 of first switch de vice 88 until plunger 94 of the second switch device 90 is engaged and the latter device actuated. At this point the parts are in the position shown schematically in Figure with both switch devices energized. v A further increase in rotative speed of shaft 30 will cause no further axial movement of the parts since the opposite end of actuator slot 48 now engages shaft pin 46.

By referring to Figure 2, it will be appreciated that the strength of each of the spring elements 70 and 72 may be varied by respectively adjusting screws 80 and 82. It is important to note that the adjustment of each spring may be achieved independently and does not affect the actuation of the other switch device.

Through the above described unique construction both ends of drive shaft 3! extend beyond casing 10 permitting the shaft to be driven from one end and the other end utilized for driving purposes if desired. Thus, should four switch operation be desired, two such units could be coupled together with one unit providing the drive for the other. Similarly it is possible to couple a tachometer or other accessory mechanism so as to be driven from such a unit.

As best seen in Figures 1 and 2 terminals 93 and 104) are provided on each of the switch devices 88 and 90 whereby the latter may be suitably connected with the appropriate devices to be controlled thereby.

I claim:

l. A speed switch actuating mechanism comprising housing means, a pair of axially spaced bearing devices mounted in said housing means, a shaft member rotatably supported in said bearing devices and including ends extending axially beyond said housing means, a speed responsive device fixed for rotation With said shaft, actuator means coaxially mounted with respect to said shaft and engageable by said speed responsive device, said speed responsive device being adapted to move said actuator means axially relative to said shaft in accordance with variations in shaft speed, a plate centrally supported upon said actuator means and conjointly defining a first pivotal axis therewith, said plate including a central aperture through which one end of said shaft is adapted to extend, a pair of spaced supporting brackets mounted on said housing means, a firstswitch mechanism mounted upon one of said brackets proximate said plate, a first spring element also supported upon said one bracket member, the other end of said first spring element engaging one end of said plate member, a second switch mechanism supported upon the other of said brackets proximate said plate, a second spring element supported upon the other bracket, the other end of said second spring element biasing against said plate, said first and second spring elements normally biasing said plate into engagement with said actuator means such that both of the switch mechanisms are de-energized when the rotative speed of said shaft is below a predetermined value, said first spring element being weaker than said second spring element whereby an increase in the rotative speed of said shaft will cause said speed responsive device to move the actuator means causing the plate to pivot about the seco'nd spring element and energize the first switch mechanism, a continued increase in the rotative speed of said shaft causing the speed responsive mechanism and the actuator means to pivot said plate about said first switch mechanism to compress the second spring element and actuate the second spring device.

2. A speed switch actuating mechanism comprising housing means, a pair of axially spaced bearing devices mounted in said housing means, a shaft member rotatably supported in said bearing devices and including ends extending axially beyond said housing means, a speed responsive device fixed for rotation with said shaft, actuator means coaxially mounted with respect to said shaft and engageable by said speed responsive device, said speed responsive device being adapted to move said actuator means axially relative to said shaft in accordance with variations in shaft speed, a plate centrally supported upon said actuator means and conjointly defining a first pivotal axis therewith, said plate including a central aperture through which one end of said shaft is adapted to extend, first and second switch devices mounted on said housing proximate the plate, first and second spring members respectively associated with the first and second switch devices and normally biasing the plate into engagement with the actuator means, the respective strengths of the spring members being such that each will be compressed by actuator means movement at a difierent speed of the shaft member permitting sequential energization of the switch devices by the plate.

3. A speed switch actuating mechanism as set forth in claim 2 in which the first and second spring members are aligned on opposite sides of said first pivotal axis.

4. A speed switch actuating mechanism as set forth in claim 2 in which the end of said shaft extending through the plate aperture intersects the first pivotal axis and terminates intermediate the first and second switch devices.

5. A speed switch actuating mechanism as set forth in claim 2 in which the switch devices and the spring members are mounted on the exterior of the housing means and further in which both ends of said shaft member extend exteriorly of the housing means with said one shaft end terminating intermediate the switch devices.

6. A speed switch actuating mechanism as set forth in claim 1 in which said brackets are aligned on opposite sides of the first pivotal axis, said one end of the shaft member intersecting said axis and terminating intermediate said brackets.

7. A speed switch actuating mechanism as set forth in claim 2 in which said actuator means includes an annular ring having a pair of diametrically spaced pins mounted thereon, said pins including tapered ends extending from said ring, said plate including a pair of tapered recesses disposed on opposite sides of the aperture and adapted to receive the tapered ends of said pins.

8. A speed switch actuating mechanism as set forth in claim 7 in which said pins and plate recesses are aligned along said first pivotal axis.

9. A speed switch actuating mechanism as set forth in claim 8 in which the switch devices and spring members are aligned along an axis normally dispdsed to said first pivotal axis.

References Cited in the file of this patent UNITED STATES PATENTS 2,457,192 Williams Dec. 28, 1948 

